01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together flour, baking powder, baking soda, salt, and pepper until evenly distributed.
03 - Add cold butter cubes to flour mixture. Using a pastry cutter or fingertips, work butter into flour until mixture resembles coarse crumbs with some pea-sized butter pieces remaining.
04 - Stir in grated Gruyere cheese and chopped fresh sage until evenly incorporated throughout the flour mixture.
05 - Pour cold buttermilk over dry ingredients. Mix gently with a fork just until dough begins to come together, being careful not to overmix.
06 - Turn dough onto lightly floured work surface. Pat gently into a 1-inch thick rectangle, handling dough as little as possible.
07 - Using a floured 2.5-inch biscuit cutter, cut straight down through dough without twisting. Gather scraps and press together gently to cut remaining biscuits.
08 - Place biscuits on prepared baking sheet, spacing 1 inch apart. Brush tops with milk or cream if desired for golden browning.
09 - Bake for 14 to 16 minutes until biscuits are risen and golden brown on top.
10 - Allow biscuits to cool on baking sheet for 5 minutes before serving warm.